In an hour, Sue can produce 40 caps or 4 jackets and Tessa can produce 80 caps or 4 jackets. Who has a comparative advantage in producing caps? If Sue and Tessa specialize and trade, who will gain?

What will be an ideal response?

Sue forgoes 4 jackets to produce 40 caps, so Sue's opportunity cost of producing one cap is (4 jackets) ÷ (40 caps) or 0.1 jackets per cap. Tessa forgoes 4 jackets to produce 80 caps, so Tessa's opportunity cost of produc-ing one cap is (4 jackets) ÷ (80 caps) or 0.05 jackets per cap. Tessa's opportunity cost of a cap is lower than Sue's opportunity cost, so Tessa has a comparative advantage in producing caps.
If Tessa specializes in caps and Sue specializes in jackets, both Sue and Tessa gain from trade. For instance, suppose they settle upon a price of 1 jacket for 15 caps. Sue gains because she can obtain caps from Tessa at a cost of (1 jacket) ÷ (15 caps), which is 0.067 jacket per cap, a cost that is lower than what it would cost her to produce caps herself. Tessa also gains from trade because she trades caps for jackets for 0.067 jacket per cap, which is higher than her cost of producing a cap.